Pound notation in Summation

Question

Pound notation in Summation

Sagar Patel

2015年5月24日 10:04

I was going through a paper comparing glove and word2vec. I came across the pound notation shown below. What does it mean when used like this? The link for paper is here

Topic notation machine-learning

Category Data Science

Rubens · Accepted Answer · 2015年5月24日 10:04

In the third paragraph of the first section (page 1), they define $\#(w)$, $\#(w; c)$, and $\#(c)$. Quoting such paragraph:

Word-context pairs are denoted as $(w; c)$, and $\#(w; c)$ counts all observations of $(w; c)$ from the corpus. We use $\#( w ) = \sum_c \#(w; c)$ and $\#(c) = \sum_w \#(w; c)$ to refer to the count of occurrences of a word (context) in all word-context pairs. Either $\sum_c \#(c)$ or $\sum_w \#(w)$ may represent the count of all word-context pairs.

So, considering the equation you cited:

$\#(w_i, c_j)$ counts the occurrences of a specific word $w_i$ over the context $c_j$;
and $\frac{\#(c_)}{\sum_w \#(w)}$ accounts for the the probability of having context $c_j$ in the dataset.

spikedlatte · Accepted Answer · 2015年4月30日 08:18

1

spikedlatte answered at 2015年4月30日 08:18

That just means count. #(w) is the number of times w occurs in the corpus.

Pound notation in Summation

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